The background art of the technical field includes JP-A-2013-005621 (PTL 1). This publication discloses that “in a voltage reactive power control system maintaining a bus voltage of a loop system, configured to supply power with power transmission lines formed in a loop shape through a plurality of power generation and transformer substations, in an appropriate range, the amount of reactive power in a case where phase adjustment facilities of the loop system are separately installed and opened is calculated when the bus voltage exceeds a target set voltage range, a simulation is made to confirm whether a reduction in transmission loss can be achieved and whether the bus voltage falls within the target set voltage range, on the basis of the amount of reactive power, and the phase adjustment facilities are controlled so that a setting state for performing the simulation is set in a case where it is determined that a reduction in transmission loss can be achieved and that the bus voltage falls within the target set voltage range.” (see Abstract).